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    7 Common Causes of a Noisy Water Heater

    Noisy Water Heater

    Many homeowners experience a noisy water heater, and beside the fact that its annoying, it could be an indication that there's something not working correctly. As well as the tips below, make sure you have a maintenance schedule for your water heater system

    Taking the time to diagnose the problem will not only quiet things down, but it could help you prevent further damage. This article will cover the top 7 reasons you may be experiencing a noisy water heater.

    What Causes a Noisy Water Heater?


    Man holding his ears

    Accumulation of Sediment & Mineral Deposits

    If your water heater has a significant amount of sediment and mineral deposits you might hear any of the following noises:

    Popping

    Over time sediment will accumulate inside your tank. This why performing regular water heater maintenance is so important. It will help flush the build-up and keep your unit running efficiently.

    Sediment is defined as any solid material that settles on the bottom of your water heater. It can enter your tank with the water supply in the form of sand or other debris. But it can also be minerals that are released as the water is heated. 

    Mineral Deposit Build-up

    Mineral deposit build-up is especially a problem in areas with hard water. Water absorbs minerals as it travels thru the ground. These minerals, primarily calcium and magnesium carbonate, are harmless from a health perspective.

    However, as the water is heated, they separate from the water and form inside the tank. The popping sound you hear could be caused by the lime scale build-up.

    Sediment Build-up

    Another reason you might hear popping is from the loose sediment floating at the bottom of your tank. Steam bubbles develop under the sediment and explode when the water is heated. The popping sound is actually the steam bubbles exploding! 

    When a water heater is not flushed on a regular basis, sediment will begin to build-up at the bottom. In some cases this can reach a point where flushing the tank is no longer be possible. 

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    Rumbling

    As the water temperature rises the water within the tank expands, and begins to escape from under the sediment. The rumbling sound you hear is the water making its way thru the sediment.

    If you're able to hear a rumbling sound, there's a good chance  that the sediment build-up has reached a critical level. Although, not dangerous, it is an indication that your water heater is not operating efficiently.

    You should attempt to flush the sediment build-up from the tank. Be aware that this is a red flag that your tank may be prone to having future problems which may require you to replace it in the near future.

    Crackling, Sizzling, Hissing, or Popping

    If you own an electric water heater and you hear Crackling, Sizzling, Hissing, or Popping, there's a good chance that the sediment build-up has buried the lower heating element. 

    When this happens, you should drain the tank and remove the heating element so that you can clean any sediment and lime scale build-up from the element.  Soak it in vinegar and then gently use a wire brush. 

    If you are unable to drain your water heater because the sediment build-up is clogging the drain valve. You'll need to purchase a new water heater. However, you many choose to wait until your tank begins to leak before replacing it.

    We highly recommend purchasing a water heater leak detector. These alarms will help prevent a huge mess and will alert you when it detects water leaking from the tank. They are inexpensive and easy to use, best of all they will allow you to react quickly before you have 60-gallons of water on the floor. 

    Water Alarm
    Glentronics, Inc. BWD-HWA 00895001498 Basement Watchdog High Water Alarm, Multi

    Restricted Water Flow

    Sizzling

    A Sizzling sound is usually an indication that your water heater has restricted water flow. There are a few valves that can cause this irritating sound.

    • Check the T&P relief valve. This is a safety valve designed to allow water to escape if the tank ever builds up too much pressure. If the sizzling sound is coming from the T&P valve, we recommend shutting down the water heater by turning off the power and water. Then contact a professional plumber.
    • Check the water inlet valve to ensure that it's fully opened. This is the water valve that allows the incoming water to enter the water heater.
    • Check all of the other water lines and valves, including the water outlet valve to make sure there are no kinks in the lines. Also check that the valves are fully opened.

    Water Pressure Fluctuations

    Ticking

    A ticking sound is typically caused from pressure fluctuations within the plumbing. Frequently, water heaters use water inlet and outlet nipples with heat traps. These nipples are where the plumbing connects to the heater. They also help improve the unit's efficiency. If you find that this is the source of the ticking, you can simply remove and replace them with a non-heat trap nipple

    Dielectric Nipples
    Camco 10623 Dielectric Nipples

    Household Plumbing

    A noisy water heater could also be the result of your home's plumbing, and the problem may not be your water heater at all. As the pipes leave your water heater, they expand and contract as the water temperature warms and cools. 

    As the pipes expand they could rub against the wood framing and loose straps, resulting in a ticking sound. Follow the sound and try to pinpoint where its the loudest. Then secure the pipe tightly or install spacers to keep the pipes from moving.

    Sometimes if you reduce the temperature of the water heater by a few degrees you'll be able to reduce the pressure which, in turn will eliminate the noise.

    head phones lined up on a pipe

    Leaks & Condensation

    Sizzling

    If you have a gas hot water heater and you notice a sizzling sound when the burner is ON, there's a good chance that you have an issue with condensation.

    When condensation forms it can drip onto the burner components. When the burner is hot you'll hear a sizzling sound as the condensation drips.

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    Water Heater Leaks

    A leak inside the heater can also be the cause of a noisy water heater. When this is the problem, you'll typically hear a sizzling sound when the burner is off.

    Check your water heater for leaks, you may find a puddle nearby. In many cases a sizzling sound is cause for contacting a professional plumber.

    Water Source

    Popping

    If your anode rod is made of aluminum and your water supply has a high pH level a reaction called aluminum hydroxide may occur. This is actually very common in areas that have chlorine/chloramines in the water supply, since chlorine has a pH level of 11.7.

    When this reaction occurs, a gel-like substance forms at the bottom of the tank and/or the anode rod. The tank will need to be flushed and delimed. Then replace the sacrificial anode rod with one made with magnesium. 

    Magnesium Anode Rod
    Reliance 9001829005 32-Inch Magnesium Water Heater Anode Rod

    Water Hammer

    Knock or Hammer Sound

    A noisy water heater can make an especially annoying sound. When water is abruptly shut off you might hear a knock or a hammer sound. This is called water hammer.

    When the water flow was abruptly stopped, there's no place for the water to go. So it flows in reverse back to its original source, in this case, your water heater.

    Water hammer can be very destructive, and although the problem did not originate from your water heater it could create a serious issue. It has the potential to not only cause a pipe to burst within your home, but there can even be enough force within the pipes to cause the tank shell to expand, collapse a flue tube, or even deform the top of the tank!

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    Installing a Water Hammer Arrestor can protect your plumbing and water heater. These devices absorb the shock wave  created when the flow of water abruptly ends. The water hammer arrestor is designed with an air chamber inside which absorbs the shock once the pressure reaches the device. 

    Water Hammer Arrestor
    Sioux Chief Mfg 660-TK Female Swivel Ballcock Nut by Male Ballcock Thread Mini Rester

    Heating Element

    Humming

    Electric water heaters can sometimes create a humming noise. There are two heating elements, an upper and a lower. It's not uncommon for the upper heating element to vibrate and hum when cold water flows into the tank and circulates around the system.

    Although, the humming noise can be annoying, its generally not harmful to either the heating element or the water heater. Simply use an element wrench to tighten the heating element and your noisy water heater should be quiet again!

    Heating Element Wrench
    Camco 09953 TRV117743

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